Design of a New Refractive Index Bio-Sensor Based on Photonic Crystal Suitable for DNA Sensing

In this paper, a novel biosensor based on the photonic crystal for refractive index measurements is proposed and investigated. Three designs, known as single-cavity structure, duble and triple-cavities structures, are designed and studies. All the structures were composed of a main hole as a ring resonator localized between the input and output waveguides. Two-dimensional finite-difference time domain and plane-wave expansion methods are employed to study the output power spectrum of the structures. By absorbing DNA molecules in the PBS solution, the refractive index of the sensing holes differ which results to the output transmission spectrum of the structure shift and hence, the sensing process occure. We study the impact of different parameters on the sensing of the structures. Results show that the sensitivity of the sensor depends mainly on the geometrical properties of the defect region of the photonic crystal structure. Results shows that the single cavity and triplet structures have the best sensitivity equal to 345nm/RIU and 531compared to the other proposed sensors, respectivelly.